The goal of these studies is to provide mathematical models of the natural history of carcinoma of the cervix, adenocarcinoma of the endometrium and carcinoma of the breast. These models will be used in the establishment of meters to employ in the optimization of the application of diagnostic and screening tests for gynecological cancer. For each of the three diseases of interest here there is a vast body of literature pertaining to the epidemiology, etiology, screening, treatment and follow-up of patients. I will use existing data bases to continue my work on the development of probability models of use in describing the natural history of these lesions in the individual and/or the aggregate. In addition, I will use these results in order to examine methods with which to evaluate the effects of screening for each lesion on the expected longitudinal experience in the individual and in the aggregate as measured by the indices - incidence, mortality and survival. I will also attempt to contrast the effects on these estimators that may result from using alternative screening strategies, such as screening "high-risk" subsets of the population.